How to know the list of people who gave a Google Plus One (+1) to the website. The Facebook likes people list are displayed when clicking the like count button, but +1 doesn't displays any user IDs that gave a plus? Any ideas?

Not an answer to the "my site +1's", but for a Google+ Post, you can click on the "People who +1'd this" link to get the list. (It's the link under the +1 icon that is the current number of +1s.)
– MufasaNov 7 '11 at 17:00

1

@BusinessInelligence Blogs posts in the Blogger admin pages list +1s for posts that have been liked. Clicking on the +1 link sometimes reveal name of the person who +1-ed it. It appears that the name shows up only if users have opted to display it through some setting.
– mvarkSep 2 '12 at 15:12

3 Answers
3

I don't think it is possible to determine the identities of the people who gave a Google +1 to a website or URL, whether on your own website or one that you don't control. This wasn't announced until 27 Jun 2012 by Google, a long time after you asked your question! Now Google policy seems quite explicit (emphasis mine):

Publishers may not attempt to discover the identity of a Google+ button user
unless the user consents to share his or her identity with the Publisher via a
Google-approved authorization procedure. This prohibition includes identifying
users by correlating Google+ button reporting data from Google with Publisher data.

For the avoidance of doubt, this prohibition includes, but is not limited to, any use of pixels, cookies, or other methods to recognize users’ clicks on a Google+
button... Publishers may not direct users to click a Google+ button for purposes
of misleading users...

I don't know what Google-approved authorization procedure is referred to in the first sentence.

Google Webmaster Tools reports on all +1 interactions for your
content, regardless of whether the interaction occurs on your own
domain, or on a search result listing.

However, Google Webmaster Tools also aggregates reports on +1 activity related to your content, so no further detail can be determined.

Blogger and other social sharing

As @mvark mentioned, on a Blogger blog, if one is the owner, the admin panel displays how many +1's were given to each post (URL). Sometimes the person's identity is disclosed. That seems to be dependent on a variety of factors that include

Designating that one's Google+ activity on non-Google and Google sites be publicly visible. This setting is in the user permissions page for one's own Google account; and

Possibly if one has some form of Google+ circles relationship with another user who has +1'd that same URL. I have noticed this on non-Blogger websites as well.

EDIT

Here is a very recent page, from 29 October 2012, Google Developers, about Social Tracking. It has new information about Google+ tracking as well as Twitter and Facebook likes and un-likes. There is also a new Google+ private beta program, that might allow you to do what you requested, but I'm not sure who is eligible to participate in it.